1. Field of the Invention
The present invention relates to an automatic tracking method for a golf swing, and in particular, to a method for automatically tracking a colored mark attached to a shaft of a golf club or/and a body of a golfer on a camera photographed image.
2. Description of the Background Art
A motion-diagnosing apparatus as shown in FIG. 7 has been conventionally disclosed in Japanese Patent No. 2794018 as an apparatus for analyzing a golf swing.
The motion-diagnosing apparatus includes: a TV camera 2 photographing a swing motion of a person 1 to be diagnosed; a processing apparatus 3 connected to the TV camera 2 and a CRT 4 displaying a result of the diagnosis, wherein provided on the person 1 to be diagnosed are movement points P1 to P6 at which reflecting tapes are adhered.
The processing apparatus 3 includes: means for converting image data transmitted from the TV camera 2 to digital signals; means for extracting coordinates of movement points P1 to P6 from the image data; means for conducting an arithmetic operation on the coordinates of the movement points P1 to P6 into numerical data showing characteristics of the motion; means evaluating the obtained numerical data by comparing it with numerical data of comparative reference; and means for diagnosing the swing based on evaluation values.
The movement points P1 to P6 on the image data are individually provided with respective window frames enclosing them so that each of the movement points P1 to P6 is recognized in a corresponding window frame and individually tracked.
In swing analyzing apparatuses disclosed in Japanese Patent Application Laid-Open Nos. 2001-614 and 9-154996, sensors capable of measuring an axial direction are attached to a wrist or the like to obtain a wrist joint angle or the like and to thereby detect a motion of a player and analyze a swing thereof.
According to a motion-diagnosing apparatus disclosed in Japanese Patent No. 2794018, however, a risk arise that a background image other than the movement points P1 to P6 is erroneously recognized as the movement points P1 to P6 in a case where in the background image other than the movement points P1 to P6, there are present sites close to the movement points P1 to P6 in luminance and color. Furthermore, a problem arises that if a person 1 to be diagnosed actually conducts a swing motion, the movement points P3, P4 and P6 attached to a shoulder, a hip and the like are hidden by movement of an arm to thereby cause tracking error in regard to the movement points P1 to P6, thereby reducing a measurement precision.
Moreover, not only does a problem arise that in a case where the different movement points P1 to P6 are superimposed one on another when viewed from the TV camera 2, as well, a failure occurs in tracking of the movement points P1 to P6, but a risk also occurs that in a case where the movement points P1 to P6 become close to one another in position when viewed from the TV camera 2, though not being superimposed, plural ones of the movement points P1 to P6 are detected in a window frame, leading to an erroneous recognition of the movement points P1 to P6.
In Japanese Patent Application Laid-Open Nos. 2001-614 and 9-154996, not only is it hard to measure many of points because of use of a sensor, but a possibility also arises that a swing different form an essential swing of a person to be diagnosed is sensed under an influence of a sensor being attached to the body of the person to be diagnosed even if a movement of one site is measured.